Model airplane starting unit



July 12, 1949. G. H. MccoRMlcK ET AL 2,475,750

MODEL AIRPLANE STARTING UNIT Filed Nov. 3, 194'? 2 Sheets-Sheet 2INVENTORJ. (eorge HM? format/ Thomas LMcrmz'c/ Patented July 12, 1949MODEL AIRPLAN E STARTING UNIT George H. McCormick and Thomas L.McCormick, Rock Island, Ill.

Application November 3, 1947, Serial No. 783,678

1 Claim.

O'ur present invention relates to an improved model airplane enginestarter of the type especially designed for use by model airplaneenthusiasts to eliminate the diicult and troublesome task of manuallywinding the propeller to start the engine.

In the miniature motors used in model planes it is impossible -forproper working conditions to employ mechanical or electrical starters onthe plane, and therefore we have devised the device of our inventionwhich consists in a portable motor and battery which may be easilyconnected with the nose of the propeller hub to rotate the propeller andengine until it starts to fire.

In the accompanying drawings we have illustrated one complete example ofthe physical embodiment of our invention according to the best mode wehave thus far devised, but it will be understood that various changesand alterations may be made in the exemplified structure Within thescope of the appended claim.

In the drawings:

Fig. 1 is a front elevational view of the device of our invention.

Fig. 2 is a side elevational view thereof.

Figs. 3 and 4 are end elevational views of the housing sectionsseparated.

Fig. 5 is a sectional view at line 5-5 of Fig. 1.

Fig. 6 is a detail view of the main switch.

Fig, 7 is a diagrammatic view of the electrical circuit.

Referring now to the drawings wherein we have illustrated the presentpreferred embodiment of our invention we employ a housing or casingconsisting of the lower section 2 and upper section 4 secured togetherby screws 6. The upper section 4 has a handle 8 for ease of carryingsecured by screws I0 and the lower section is shaped to secure aconventional storage battery I2, having terminals I4 and IB.

A motor I8 has lugs 20 through which the screws 22 secure the motorwithin the upper section. The driven shaft 24 of the motor is attachedin driving relation with a cylinder 26 journaled in collar 28, and thehub 38 of the cup 32 is secured by set screw 34 in the cylinder. Aninterior rubber liner 36 is provided in the cup, and the hub is recessedat 38 to accommodate the bolt 4I) which secures the shaft and thecylinder.

A pair of opposed brackets 42 and 44 on the motor are drilled to receivethe bolts 46 and 48 on which are slidably mounted the cross arms 50 and52 having contacts 54 and 56, the arms being resiliently spaced byspring 58.

A switch 60 is located in the upper section to open the circuit when thedevice is not in use and to prevent accidental operation of the motor asWhen the starter is being transported. A contact plate 62 is housed ininsulating block 64 and engages the contact block 66 when the sectionsof the housing are in assembled position.

Connectors 68 and 'IIJ in bases I2 and 74 permit the use of auxiliary orbooster current sources if desirable.

From the above description it will be apparent that when the switch 68is closed, the hub of a propeller, not shown, of a model airplane may beinserted into the lined cup and pressed in, the contacts 54 and 56 willengage each other to close the circuit and the motor will drive theshaft and the cup to spin the airplane engine until it starts. Releaseof pressure on the cup will allow the spring to disengage the contactsand break the circuit.

Having thus fully described our invention what We claim as new anddesire to secure by Letters Patent is:

A portable starter for model airplane engines comprising a casing, asource of electrical energy within said casing, a motor secured in saidcasing, a shaft driven by said motor, a collar on said casing inalignment with said shaft, a tubular member slidably journaled in saidcollar, means slidably keying said tubular member on said shaft forrelative axial movement thereon, a cup-shaped member secured to saidtubular member, bracket means on said rmotor, bolt means secured to saidbracket means substantially parallel to said shaft, a pair of opposedcross arms slidably mounted on said bolt means, opposed contacts on saidcross arms, respectively, coiled spring means between said cross armsbiasing the same part whereby said contacts are separated from eachother and one of said cross arms abuts said tubular member, meansplacing said source of energy, motor and contacts in a series circuit,whereby the propeller hub of` a model airplane may be inserted into saidcup-shaped member to move the same toward said shaft to cause saidcontacts to close the circuit to energize said motor.

GEORGE H. MCCORMICK. THOMAS L. MCCORMICK.

REFERENCES CITED The following references are of record in the iile ofthis patent:

'UNITED STATES PATENTS Number Name Date 1,331,791 Wilkinson Feb. 24,1920 1,504,766 Knipfer Aug. 12, 1924 2,855,852 Fisher Aug. 15, 19442,431,316 Dudley et al. Nov. 25, 1947

